1. The Field of the Invention
The present invention relates generally to integrated circuits. More specifically, the present invention relates to mechanisms for operating the input/output terminals to have configurable functionality.
2. Background and Relevant Art
Electronic and computing technology has transformed the way that we work and play. Many electronic or computing systems rely on a variety of components that cooperatively interact to perform complex functions. A component typically includes a chip and a package.
The chip includes the complex circuitry that perform the functions. The chip tends to be composed of a semiconductor (e.g., silicon) or dielectric (e.g., sapphire) upon which the circuitry as fabricated.
The package allows the chip to interface with the printed circuit board, and provides some level of protection for the chip. The protection might include Electro-Magnetic Interference (EMI) shielding, temperature dissipation structures, and/or physical barrier protection against inadvertent contacting the delicate circuit structures on the chip. The package includes a number of pins that are appropriate positioned such that the package may be plugged into a socket on the integrated circuit board. Some or all of these pins may be electrically connected to an appropriate bond pad on the chip, thereby establishing an electrical connection between the chip and the printed circuit board through the package. Accordingly, the chip may receive signals and power supply from the printed circuit board via the package, while providing output signals to the printed circuit board through the package.
If the size of the package is limited by the size of the chip, the package is considered to be “core-bound”. If the size of the package is limited by the number of pins on the package, the package is considered to be “I/O bound”. In order to preserve valuable printed circuit space, it is advantageous for packages to be as small as possible for a given level of chip functionality. Accordingly, what would be advantageous are mechanisms for reducing the number of pins required for a particular level of chip functionality if the chip is I/O bound.
In addition, in order to avoid an expensive printed circuit board redesign, it is often desirable for improved chips to use the same package design as the previous chip. This would allow for the improved functionality of the new chip to be obtained by simply unplugging the old chip package from the printed circuit board, and plugging in the new chip package into the same place. This represents significant value-add since improved functionality is obtained without a printed circuit board redesign. However, often, the improved chip uses more pins than the previous chip, thereby making the newer package incompatible with the old package. What would be advantageous are mechanisms in which a new chip may be used in the same package as an older chip, despite the newer chip having significant improved functionality that would conventionally use more pins.
Furthermore, different individuals may desire the same functionality of a given chip, yet have different circuit board designs. Accordingly, one customer may have a socket that has thirty pins, and another forty pins. Yet it is desirable for both to have the same chip. Accordingly, what would be advantageous is a mechanism in which the same kind of chip may be incorporated into different packages, despite there being different numbers of pins on the packages.